Eight million people live in the Chicago area, but the number of doses of the H1N1 flu vaccine that have arrived so far only number in the thousands.
Friday, the Centers for Disease Control said production of the vaccine is going more slowly than expected.
At Loyola University Medical Center, the staff is receiving doses of the seasonal flu vaccine, but the hospital has yet to receive a single dose of the H1N1 vaccine.
"What we're seeing is people becoming ill at a time we don't yet have the vaccine," said Dr. Jorge Parada, Loyola infection control director.
Loyola usually doesn't see any flu cases in October, but this month, they've had 11. One patient is in critical condition.
The CDC had predicted 40 million doses of H1N1 vaccine would be available by the end of October. Friday, the CDC downgraded that estimate to 28-30 million.
"It will be pretty challenging to find vaccines in many areas over the next several weeks," said Dr. Anne Schuchat, CDC.
Hospitals are now preparing for the panic that comes with pandemic. Loyola recently completed a two-day drill in preparation. In the case of a pandemic, tents would be used to triage those with flu symptoms to keep them from overwhelming the E.R.
Around the nation, calls of concern are flooding doctors' offices.
For now, only health care workers and those in government-defined, high-risk groups are eligible to receive what little vaccine is available.
Rush University Medical Center says its 1,000 doses will go only to employees. Northwestern has 3,700 doses that will be used for staff and priority patients. Central DuPage Hospital says it has enough to immunize 4,000 of its workers.
For those with the flu, doctors' advice is to stay home unless you have serious symptoms and your own physician advises you to report to the hospital.
"Even if a minority do become more significantly ill, based on the number of people we expect to catch this, the health system will be stressed," Parada said.
The CDC says there will be plenty of vaccine to go around. What they can't promise is that it will be in the hands of your doctor or county clinic before you get sick.
Experts emphasize the vast majority will experience H1N1 just like any other flu, meaning it'll be an uncomfortable few days but not necessarily more dangerous than what we see every winter.
